<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport"
        content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
<script>
  // 输出结果为 1 3 2 4
  setTimeout(() => {
    console.log(1);
    Promise.resolve(3).then(data => console.log(data));
  }, 0);

  setTimeout(() => {
    console.log(2);
    Promise.resolve(4).then(data => console.log(data));
  }, 0);
</script>
</body>
</html>
